The wheels of a house trailer rotate about wheel axes perpendicular to the normal direction of travel of the trailer. These wheels are normally mounted on struts themselves pivotal about axes that are skew, that is neither intersecting nor parallel, with reference to the wheel axes. Typically each strut pivot axis is inclined inwardly upwardly and outwardly backwardly relative to the motor vehicle and its normal horizontal forward direction of travel. Such pivoting about these skew axes gives excellent road-handling capabilities, providing the right camber and caster for best roadability, with best transmission force from the center of the load to the wheels.
German Utility Model No. 7 319 964 discloses such a system with a so-called elastomeric spring axle. This is formed of a prismatic-section support tube fixed in the frame of the vehicle and provided internally with a torsion bar coupled with a wheel-support arm. The torsion bar engages the support tube by means of elastomeric webs. In order to obtain the desired pivoting about a skew axis the support tube is bent and in each bent part has a respective torsion bar and is elastomerically supported.
Such an arrangement is relatively complex and expensive to make. It is relatively difficult to service in the event that any of its parts fail. Finally the elastomeric mounting is extremely disadvantageous in that in extremely cold climates the spring characteristics for the bodies responsible for the cushion mounting change. In fact the elastic limit of such bodies decreases greatly with decreasing temperature, so that when used under very cold conditions failure is a common problem.